I've recently (and finally!) upgraded my flip phone to a smart phone. In doing so, I've discovered a bunch of really cool apps for artists. The following are in no particular order. I've included a short description for each app, but for more information, please click on the links to visit each app's page in iTunes.
1.
Accuview This app is a drawing aid that allows artists to place a grid over photos taken from a smart phone. The grid helps artists to get correct proportions and to map out compositions in their drawings.
2.
Pose Tool This app is a useful reference tool for drawing figures. You can manipulate body parts on the figure (male or female) to create custom poses.
3.
Perspective for Artists This app allows artists to create one and two point perspective grids. You can import a photo and overlay the perspective grid on top of it for accurate perspective in your drawings.
4.
Handy This app contains rotatable hands (male or female) in a number of poses.